<!DOCTYPE html>
<div id="foo"></div>
<script src="../../include.js"></script>
<script>
    test(() => {
        const foo = document.getElementById("foo");
        let animation = foo.animate({ opacity: [0, 1] });
        println(`Animation's default timeline is the document's timeline: ${animation.timeline === document.timeline}`);

        animation = foo.animate({ opacity: [0, 1] }, { timeline: null });
        println(`Animation created with null timeline has no timeline: ${animation.timeline === null}`);
    });
</script>
